The invention relates to the field of high-performance textiles and more particularly textiles possessing mechanical properties giving them resistance to laceration or the capability of detecting attempted laceration, these being called hereafter antilaceration properties. The invention is very particularly applicable in the field of tarpaulins in general, when the textile is used in combination with a coated fabric for example. It is also applicable when the textile is used as it is, to act as cladding for buildings or more generally for a vertical wall, partition or separation in constructions.
The need to give tarpaulins, especially truck tarpaulins, antilaceration properties, has given rise to various technical solutions.
Thus, it has already been proposed to produce tarpaulins by complexing a textile with a metal mesh made up from a sheathed metal strip. This solution has many drawbacks and especially the fact that, despite the use of quite an open mesh (with a typical mesh cell of 100 mmxc3x97100 mm) and containing little metallic material, this mesh very greatly stiffens the tarpaulin and makes it very difficult to handle when covering the truck with the tarpaulin. Furthermore, the completed mesh generally appears on the outside of the tarpaulin, which means that the protection is not actually concealed and leads one to believe that the truck is intended to transport valuable merchandise.
It has also been proposed to produce truck tarpaulins by coating a textile either composed entirely of metal cables or incorporating metal cables woven with other synthetic cables. These solutions also have many drawbacks. This is because when the textile is composed both in the warp direction and in the weft direction of cables strong enough and sufficiently closely meshed to withstand laceration, the weave has a very considerable relief, which necessarily means that a large amount of coating has to be deposited on each side of the metal textile in order, at the very least, to cover the top of the yarns. Such a coated textile is very heavy and practically impossible to handle during operations to cover the truck with the tarpaulin, especially in cold weather. It is also relatively complicated to cut and to make up. Moreover, since the metal reinforcing cables are incorporated right within the tarpaulin, it is necessary to create an entire range of different product part numbers in order to meet the thickness and color requirements of the various users seeking a new furnishing. In the case of an existing fleet of tarpaulined trucks, this solution means that the tarpaulins in use have to be completely replaced, even those which are only slightly worn. In addition, when a laceration cutting the cables appears, the entire wall of the tarpaulin has to be replaced, since repairs are not possible.
From the environmental standpoint, this type of textile construction makes it very difficult to recycle the materials because of the difficulty of separating the metal cables from the synthetic materials which surround them.
Finally, it is not generally necessary to reinforce a truck tarpaulin over its entire height, but only the accessible parts. The use of a textile having metal reinforcing cables over the entire height of the tarpaulin unnecessarily increases the cost of the latter and makes it difficult to make up, as already mentioned.
One problem that the invention therefore aims to solve is that of reinforcing tarpaulins without rendering the making-up operation difficult and complicated. Another problem that the invention aims to solve is that of being able to give a wide variety of textiles antilaceration properties, especially with regard to their mechanical properties, their dimensions, their colors and the markets in which they are used.
The same need for antilaceration properties exists in the case of elements similar to tarpaulins, such as claddings, and more generally, the various textile elements used in architecture to form the outer walls of tents, partitions or coverings. In this case, the textile elements may be impervious, as is the case with truck tarpaulins, but also apertured in order to allow the passage of light or to maintain visibility through them.
The invention therefore relates to a high-performance textile possessing antilaceration properties.
In accordance with the invention, such a textile is one made from synthetic cables sheathed with a polymer material, such as polyvinyl chloride, and includes, in the warp direction and the weft direction, metal cables sheathed with a polymer material having a different color from that of the polymer material for sheathing the synthetic cables, wherein the warp and weft metal cables are uniformly spaced by a distance of less than 80 millimeters.
In other words, the invention consists in using, as antilaceration textile, a textile made from sheathed cables among which are some metal cables, which thus define a square mesh cell whose sides are small enough to prevent the passage of a hand. Consequently, any laceration made by a cutting tool will be blocked by the metal cables, and the maximum dimensions over which the textile can be cut will be insufficient to let a criminal""s hand or arm pass through it.
The use of a polymer material having a different color for the synthetic cables and for the metal reinforcing cables allows these reinforcing cables to be precisely located and therefore positioned appropriately with respect to the area to be protected.
This PVC sheathing may be obtained by extrusion or by coating. Of course, this sheathing is not limited to PVC but could be made of polyethylene (PE), polypropylene (PP), silicone or any other synthetic substance possessing the ad hoc properties.
In practice, the metal cables may advantageously be cables based on carbon steel wires, having a very high tensile strength, typically greater than 50 kilograms per square millimeter and preferably greater than 350 kg/mm2.
In practice, the synthetic cables used may advantageously be composed of polyester yarns or glass yarns. The use of polyester yarns gives a certain strength to the areas lying between the metal reinforcing cables, together with good compatibility with the PVC coating.
According to another feature of the invention, the textile may include, in the warp or weft direction, electrically conducting yarns sheathed with a polymer material, such as polyvinyl chloride, having a color different from that of the polymer material for sheathing the synthetic cables and the metal cables. In other words, the fabric includes conducting yarns also uniformly distributed over the fabric. When these conducting yarns are cut following an attempted laceration, the electrical circuit into which these yarns have been inserted is therefore open, which thus allows the attempted laceration to be detected and indicated. The use of a conducting yarn sheathed with a PVC having a color different from the other yarns makes it easier to perform the operations of connecting it to the control devices.
In practice, the electrically conducting yarns may be selected from the group comprising wires based on nickel alloys and stainless steel wires.
In practice, the electrically conducting yarns are uniformly spaced by a distance of less than 300 millimeters and preferably less than 50 millimeters.
In one particular embodiment, the metal cables intended for mechanically resisting laceration may also be used for their electrical conduction properties. In other words, the metal cables intended to resist laceration are advantageously used as electrical conductors.
In one particular embodiment, the electrically conducting yarns may be connected in series along the selvedges of the textile, so as to form an electrical continuity and a single electrical circuit for the textile. The mechanically resistant metal cables may be electrically connected to the conducting cables in order to be integrated into the electrical detection circuit.
Advantageously, the textile may be associated with a device for measuring the electrical resistance of the conducting yarns, which are possibly associated with the metal cables. As soon as this resistance becomes too high, since the current flowing through the electrical yarns becomes zero following a successful laceration, this means that at least one conducting yarn has been cut and that an attempted laceration has therefore taken place.
The textile according to the invention may be used by itself or may be incorporated into a textile complex, of which it constitutes one of the layers. In the latter case, it may be advantageously associated with a coated textile in order to form a truck tarpaulin for example, which is reinforced only in the area where the characteristic layer is present. Thus, it is possible to reinforce only the lower part of a truck tarpaulin and to leave the upper part of the tarpaulin free of protective layer, and therefore lighter.
It is also possible to use the textile according to the invention in the form of a tape, or of relatively narrow bands, in order to form laceration-resistant straps. In this case, these bands may be placed in appropriate places in the textile complex in order to provide the tarpaulin with localized protection.